Clinical activity of bortezomib in relapsed or refractory gastric marginal zone b-cell lymphoma of malt type

Abstract

8567 Background: Preliminary results using Bortezomib in relapsed or refractory gastric marginal zone (MALT) non Hodgkin’s Lymphoma patients (pts.) seem to indicate a relevant clinical activity. Aim of the present study is to investigate the efficacy of Bortezomib in this setting. Methods: The study population included 16 pts. (10 men, 6 women with a median age of 59 years) with histologically proven gastric MALT lymphoma relapsed and treated with more than one prior treatment. Stage of disease at diagnosis was II in 10 pts. and IV in 6 pts. (Lugano staging system). Gastric mapping protocol was used in all pts. to obtain multiple biopsies that allowed us to monitor histology, molecular status (PCR for the IgH gene, RT-PCR for t(11;18) and FISH analysis t(11;18), t(1;14), t(14;18), t(3;14). Bortezomib 1.3 mg/m2 was administered on days 1,4,8 and 11 of a 21 day cycle, for up to 6 cycles. Response and progression are determined by International Workshop Criteria. Median follow-up was 26 months. Results: After 3 cycles of Bortezomib histologic complete (CR) and partial (PR) responses (criteria of Wotherspoon) were observed in 8 pts. (4CR + 4PR). The pts. with stage IV disease at study entry obtained a stable disease. Molecular studies showed the persistence of the malignant clone in six pts. with histologic response (2CR + 4PR). At the end of treatment, two pts. with PR achieved CR, molecular studies showed residual disease in four pts. After a median follow-up of 26 months, only two pts. relapsed at 12 and 13 months respectively. Conclusions: These preliminary results suggest that Bortezomib is active and safe in relapsed or refractory MALT lymphomas and encourage us to complete the studies accrual. No significant financial relationships to disclose.